In my long quest to pin point my Polish mominlaw's roots, Vadim Verenich's new MDLP World calculator makes me wonder if it could be Sorb's- a Western Slavic people of Central Europe living predominantly in Lusatia, a region on the territory of Germany and Poland (from Wikipedia). Here are her results:

Both her mother and father claimed 100% Polish and were from Northern Wisconsin towns with large Polish (and German) populations. Her ancestors came to Wisconsin sometime in the late 1800's, and much of the history of where in Poland they came from has been lost. Is this result enough to think Sorb could be real, or might it be an artifact of Polish and German lines mixing? Her mtdna is T2b7a1 and she is PL9 for Eurogenes and DOD867.

As I understand it, western Slavs includes Sorbs and Poles. There are some cultural difference, and this is mainly due to the fact that the term Sorb is most often used for those who are genetically (and culturally) Slavic while residing in German territories. Today, this would comprise regions in eastern Germany, such as Saxony and Berlin-Brandenburg, but, in past times, this would have included Silesia(cities such as Wroclaw and Poznan).